Henry III (reigned 1216-1272), John's son, was only nine when he became king. By 1227, when he assumed power from his regent, order had been restored based on his acceptance of Magna Carta. However, the king's failed campaigns in France, his choice of foreigners as friends and advisers, together with the cost of his scheme to make one of his younger sons king of Sicily and help the Pope against the Holy Roman Emperor, led to further disputes with the barons and united opposition in Church and State. The Provisions of Oxford (1258) and the Provisions of Westminster (1259) were attempts by the nobles to curb the king's power, control appointments and set up an aristocratic council.

Henry renounced the Provisions in 1264 and war broke out. The barons under their leader, Simon de Montfort, were initially successful, but Henry and his son, Edward, finally defeated and killed de Montfort at the Battle of Evesham in 1265. Royal authority was restored by the Statute of Marlborough (1267), in which the king also promised to uphold Magna Carta and some of the Provisions of Westminster.